Welding is used in various manufacturing and construction applications to join various metal pieces together to form a unitary piece. An arc welding system typically includes an electric power supply coupled to a welding gun that houses an electrode that is located in the handle. The electrode completes an electrical circuit with a source of power when the electrode is placed against a piece of metal to be welded. The contact between the electrode and the piece of metal produces an electric arc between the electrode and the metal piece. The heat of the electric arc is concentrated on the metal piece, or pieces, to be joined, thereby melting the metal piece(s). A filler material is added to the molten metal, which subsequently cools and solidifies, joining the metal pieces together.
Metal Inert Gas (MIG) welding is one type of arc welding. MIG welding is also referred to as “wire feed” or Gas Metal Arc Welding (GMAW). In MIG welding a metal wire is used as the electrode to produce the arc. The wire is shielded by an inert gas and the metal wire acts as the filler for the weld. The inert gas is used to shield the electric arc from contaminants and gases that may react with the weld. Typically, the wire and gas are fed through a hand-held welding gun. The wire and gas are fed to the welding gun from a welding system having a wire feeder, a power source and a source of gas.
FIG. 1 illustrates a typical prior art welding gun 10. The welding gun typically includes a switch or trigger 12 that is coupled to the rest of the system. The welding gun includes a modular switch assembly 14 that is configured to be actuated by an operator's index finger. The switching mechanism inside the trigger is a conventional open/close contact mechanical switch, having a plurality of mechanical connections and moving parts. When the trigger is actuated, gas and wire are fed through the handle 16 and the curved delivery tube and nozzle 18, and power is applied to the welding wire, not shown.
Other types of welding, such as submerged arc welding, utilize wire guns that include switches or triggers. In submerged arc welding, a trigger is actuated to feed flux and wire through the welding gun. The triggers and switches of typical prior art welding guns include mechanical connections and moving parts, such as springs, stems or the like.
Various welding guns also include a trigger locking mechanism so that an operator does not have to constantly press the trigger in order to maintain activation. The locking mechanism is configured to allow for a quick release. Thus, when the operator is finished welding, the operator simply engages the quick release to finish activation.